1. Field of the Invention
The present invention relates to an end surface polishing device and an end surface polishing method for polishing an end surface of a rod-shaped member such as ferrule supporting an optical communication fiber.
2. Description of Related Art
An optical communication fiber is formed by smoothly polishing ferrule end surface as well as fiber end surface like a mirror finished surface after attaching a fiber in a central hole of the ferrule that is a main member of a connector. When the finished ferrule surface and the polished fiber surface are not perpendicular to the center axis of the ferrule or there is a flaw on the polished surface, there is a problem of deteriorating the accuracy in the opposed position and increasing a loss in an optical connector formed by connecting the ferrules in an opposed way. Therefore, it is necessary to polish the ferrule surface containing an optical fiber with a high accuracy.
As the conventional end surface polishing device for polishing a rod-shaped member such as ferrule containing an optical fiber, there is a technique disclosed in, for example, JP-A-3-26456. The optical fiber end surface polishing device disclosed in this publication has an eccentric disc which rotates on a concentric circle of a rotating disc and a planet gear for transmitting the rotation of a motor for revolution to the eccentric disc, so to rotate and revolve a polishing plate in combination with the above, and the end surfaces of a lot of ferrules supported by a holder are pressed to a polishing member attached to the polishing plate, hence to be polished. In the ferrule polishing by using this end surface polishing device, polishing amount is controlled by the polishing time.
In the ferrule end surface polishing, however, it is necessary to polish the ferrules so that the length of the polished ferrules should be within a predetermined range. When the length of the ferrules is controlled according to the polishing time, there causes a large error between the actual polishing amount and the above and a highly accurate control of the polishing amount is difficult.
Further, in the conventional ferrule end surface polishing, generally, it is necessary to perform several times of polishing including rough polishing, medium polishing, and finish polishing. It is very troublesome to control the length of the polished ferrules of a final finish while watching the length of every polishing.
Further, in the conventional ferrule end surface polishing, it is necessary to measure the polishing amount of the ferrules after removing the ferrules from the holder. This is a troublesome work and takes a long time for the polishing processing.
In consideration of the above problems, an object of the invention is to provide an end surface polishing device and an end surface polishing method capable of controlling the polishing amount of a rod-shaped member and shortening the polishing processing time.
A first mode of the invention to solve the above problems is an end surface polishing device for polishing a rod-shaped member attached to a holder in a pushing way, with a polishing member attached to a polishing plate provided on a main body and supported in a rotational and slidable way, which device is characterized by comprising distance detecting means for detecting a position of the holder from a reference position having no movement in a vertical direction with respect to a rotational direction of the polishing plate, or variation amount of a position varying according as length of the rod-shaped member varies, during the polishing or during the rotation of the polishing plate.
A second mode of the invention is the end surface polishing device, in the first mode, characterized in that the distance detecting means detects a relative position of the holder and the polishing plate.
A third mode of the invention is the end surface polishing device, in the first mode or the second mode, characterized by comprising measuring means for measuring the actual polishing length of the rod-shaped member supported by the holder, from the position detected by the distance detecting means.
A fourth mode of the invention is the end surface polishing device, in the first mode, characterized in that the distance detecting means detects the distance between a predetermined position moving together with the holder and a predetermined position of the polishing plate.
A fifth mode of the invention is the end surface polishing device, in one of the first to the fourth modes, characterized in that the main body is provided with supporting means for supporting the holder in a movable way toward the polishing plate and pressing means for pushing the supporting means toward the polishing plate with a predetermined pressure.
A sixth mode of the invention is the end surface polishing device, in the fifth mode, characterized in that the distance detecting means is fixed to the supporting means and the distance detecting means moves according to the movement of the holder together with the supporting means.
A seventh mode of the invention is the end surface polishing device, in one of the first to the sixth modes, characterized in that the main body is provided with pressure detecting means for detecting a pressure for pushing the rod-shaped member supported by the holder to the polishing member and the measuring means measures a polishing length of the rod-shaped member when the pressure detecting means detects a predetermined pressure.
An eighth mode of the invention is the end surface polishing device, in one of the first to the seventh modes, characterized in that the distance detecting means is a contact-typed or non-contact typed sensor.
A ninth mode of the invention is the end surface polishing device, in one of the first to the eighth modes, characterized in that the distance detecting means is able to detect 1 mm and less variation amount of the actual polishing length of the rod-shaped member.
A tenth mode of the invention is the end surface polishing device, in one of the first to the ninth modes, characterized in that the holder supports a plurality of the rod-shaped members and the rod-shaped members are polished at once by the polishing member.
An eleventh mode of the invention is the end surface polishing device, in one of the first to the tenth modes, characterized in that the rod-shaped member is ferrule.
A twelfth mode of the invention is an end surface polishing method for polishing a rod-shaped member attached to a holder in a pushing way, with a polishing member attached to a polishing plate supported in a rotational and slidable way, which method is characterized by polishing while measuring the polishing length of the rod-shaped member by detecting a position of the holder from a reference position having no movement in a vertical direction with respect to a rotational direction of the polishing plate, or the variation amount of a position varying according as the length of the rod-shaped member varies, during the polishing or during the rotation of the polishing plate.
A thirteenth mode of the invention is the end surface polishing method, in the twelfth mode, characterized by polishing while measuring the polishing length of the rod-shaped member by detecting a relative position of the holder and the polishing plate.
A fourteenth mode of the invention is the end surface polishing method, in the twelfth mode, characterized by detecting a pressure for pushing the rod-shaped member supported by the holder toward the polishing member and measuring the polishing length when the detected pressure is a predetermined pressure.
A fifteenth mode of the invention is the end surface polishing method, in one of the twelfth to fourteenth modes, characterized by moving the holder toward the polishing plate and stopping the movement of the holder when the measured polishing length of the rod-shaped member becomes a predetermined length.
A sixteenth mode of the invention is the end surface polishing method, in one of the twelfth to the fifteenth modes, characterized by moving the holder toward the polishing plate and moving the holder to an opposite side to the polishing plate when the measured polishing length of the rod-shaped member becomes a predetermined length.
According to the invention, since it is possible to detect the distance between the holder and the polishing plate by the distance detecting means and measure the polishing length of the rod-shaped members by the measuring means, it is possible to measure the polishing length of the rod-shaped members even during the polishing. Thus, it is possible to control the polishing amount of the rod-shaped members at ease and with high accuracy and also shorten the polishing processing time.